Eastern Box Turtle: Disappearing Gems of the Forest
Oct 15, 2008
The Eastern box turtle, Terrapene carolina carolina , is probably the most commonly known turtle to anyone raised in the east. Common as they seem to be, scientists claim that they are declining, and that the turtles we now see are ghost representatives of the species….they are all older adults. Why they are disappearing and what can you do to help save them? Landowners of large blocks of forest are in the best position to ensure persistence of the species. But, first, let’s learn a little about the animal.
They occur from Georgia to southern Maine, westward to Michigan, and southwest as far as the Mississippi River bordering Illinois. Eastern box turtles are found from sea level to high up in the Appalachian Mountains. However, most turtles live at lower elevations. It get its name from the fact that it can tuck its head, legs and tail inside its shell and completely close up like a box. The turtle closes up by moving a hinge running side to side across the plastron or lower shell, and then tucking the plastron up into the carapace or upper shell.
The shell consists of living bone and is part of the animal’s skeleton. Its backbone is attached to the inside of the carapace or upper shell. Adult box turtles are small. Their shell is only four to six inches long and has a distinctive high dome. The bony shell is covered with plates, called “scutes.” Scutes are made out of “keratin”, the same material that makes up your fingernails and hair.
Photo by Hill Welford
There’s a lot of variety in the markings and colors on eastern box turtles.
Many adult males are brilliant yellow, orange or red, although some are not so colorful. Females are typically dull yellow and brown, although some show a bit of color. A box turtle’s colors and markings help to hide it or camouflage it from predators, that is, from an animal that would eat it. Male box turtles have a flatter carapace than females. However, the difference is sometimes difficult to see. It is easier to tell the sex by the shape of the plastron. In males, the plastron usually curves inward behind the hinge. This helps the male to fit onto the back of the female during mating. In females, the plastron is nearly flat.
Most males have reddish eyes, while most females have brown or yellowish-brown eyes. But eye color does not always tell you the sex of a box turtle. Fully-grown males usually are larger than females.
Box turtles typically live in forests where there is plenty of cool shade in the summer and some sunny, open spots where turtles can warm up. The moist soil is good for digging burrows, and there is plenty of leaf litter, fallen tree branches and other woody piles where turtles can find shelter. There are other habitats or places in and around forests where box turtles also spend time. They visit streams and ponds, wetlands, where the ground is always muddy and often has a layer of water on it, and meadows, or grassy fields. Today, box turtles also use lawns, flowerbeds and backyard ponds around houses near the woods.
Most box turtles have home ranges or areas where they live their entire lives. Home ranges can be as large as 12 acres (or about 9 football fields), although they are often much smaller. Home ranges of different turtles overlap or share common space. This overlap makes it possible for turtles to meet and breed. Box turtles don’t’ reach adulthood or breeding age until their teens.
In the spring, the animals come out of their winter burrows. As the weather warms up, the turtles move through their home ranges, looking for food, water and mates. Adult box turtles appear to find each other pretty much by chance. However, there may also be some special odors given off by females that attract males. The female lays 1-9 eggs several months after mating. Most egg laying occurs in early summer, although females may lay eggs up through fall. Females often go into meadows or sunny, open spots in the woods to lay their eggs. They also use lawns and sunny flowerbeds around houses near the woods. Here the soil is warm, which is good for the developing eggs. The sex of the offspring depends on the temperature of the nest. Warmer nests tend to produce more females whereas cooler nests tend to produce more males. A female lays only a few eggs at a time. The eggs are soft and white, and just over an inch long. Nests are shallow, only a couple of inches deep. This is as far down as the female’s hindlegs can dig. Once she lays the eggs, she carefully buries them, and then moves on, abandoning the nest. It is easy for many animals to find these shallow nests and help themselves to a tasty snack. Many snakes, birds, mammals and even some insects eat box turtle eggs. Incubation lasts 50 to 90 days, depending on soil temperature. Most hatching occurs in late summer and early fall. You almost never see baby turtles. They spend most of their time under the leaf litter, hiding from predators.
With the coming of hot summer weather, box turtles move around less during the middle of the day. They are most active in the morning, late afternoon and after rain showers when it’s coolest. During the summer, these turtles may travel long distances to ponds, streams and wetlands to find food and water, cool down and get away from biting insects. The turtles also may burrow in the cool soil or beneath rotting logs in the forest.
Summer is the major season for feeding. Box turtles eat many types of invertebrates, such as earthworms, snails, slugs, millipedes and a variety of insects. They also eat carrion, or dead animals. Box turtles also eat small lizards, and the eggs and chicks of birds that nest on the ground. Their diet also includes many types of plants, such as wild violets and strawberries, and fungi, such as mushrooms.
As fall approaches the days get cooler. The turtles take advantage of sunny days to warm up in the sunshine. At night and on cooler days, they may burrow down in the leaves, often wedged up against fallen branches. As the days and nights get colder, the turtles eat less and less. Eventually, they completely stop eating, as they get ready for the cold winter ahead. Since turtles are reptiles and cannot produce their own body heat, they depend on the sun and warm ground to heat them up. So when it gets cold, they get cold too and can no longer digest food.
In late summer and early fall, box turtles look for a place to spend the winter. It is often a shallow burrow in the forest where lots of leaves collect, such as old tree root holes, tree stump holes, and vine tangles. The leaves and soil, and any snow that falls on top, help to protect the turtles from extreme temperatures and from rapid changes in temperature. Rapid changes can be especially harmful.
Even under the soil, leaves and snow, winter temperature can get quite cold. For box turtles, all the activity in their body, including their heart rate, slows way down. If there are a few warm days, box turtles may become active again and change their winter resting site. This can be risky. If the weather suddenly gets cold again, a turtle can die if it is out moving around. Also, when there isn’t enough snow on the ground to properly insulate turtles, long periods of extreme cold may kill those with very shallow burrows. A healthy box turtle is well adapted to deal with cold winters. However, harsh winters are quite stressful on animals that are sick or otherwise have weak immune systems. When these turtles emerge in the spring, they may suffer from such illnesses as respiratory and ear infections. These problems can be life-threatening.
How long do wild box turtles live? We don’t know for sure. Most never reach adulthood. For the lucky ones that do, most probably live less than 50 years. However, there are records of wild box turtles living much longer, some more than 100 years! Traditionally, aging was done by counting the rings on the scutes. The problem is that in good years, a turtle may have several growth spurts and lay down more than one ring. So, one ring does not always equal one year. Also, as a turtle ages, the ridges on the rings wear down making them difficult to count. Scientists often determine the minimum age of a turtle by uniquely marking the turtle’s shell in some way, such as by drilling tiny holes or filing small notches into the edge of the shell. The markings last for the life of the turtle. Whenever the animal is caught again, its age since the first marking can be recorded.
How do box turtles defend themselves from predators? A turtle’s best defense is to hide or close up its shell. Most animals can’t bite through or pry open the shell of a healthy adult box turtle. However, predators can open the shell of sick, weak animals. They can also take turtles that are too cold to react and defend themselves in the wintertime. Also, fire ants may be able to find a little space between the top and bottom shell to crawl in and attack a healthy turtle. Box turtles sometimes respond to danger by trying to run away. Clearly they can’t win that race! Many mammals and birds, and some snakes and ants can successfully attack and eat them. Box turtles are particularly easy targets for predators during the first few years of life. Their small size and soft shell leaves them with no real defense other then hiding. They can’t even close their shell until they are about one year old.
The greatest threat to box turtles is the loss of their habitat, the places where these turtles live. The Middles Peninsula and Northern Neck were once large forests broken only by wetlands, creeks, and a few meadows. But now it is made up of little patches of forest separated from one another by houses, towns, shopping areas, cropfields, development, and roads. As the turtles move through their home ranges, many eventually wander out of the forest patches. They face many dangers outside the forests and many never return. Over time, there will be fewer and fewer box turtles living in the forest patches. It will be even more difficult for turtles to meet and thus they will breed less often. Fewer turtles are born and survive because there are fewer eggs laid, fewer good nesting sites and more predators, like raccoons. (Raccoon populations increase around human dwellings). The forests themselves and the surrounding area may change so that they no longer supply the food, water and shelter the turtles need. Slowly the turtle population decreases . . . until there are no turtles left.
So what are the threats to box turtles as they wander out of the forest? The biggest problem is collisions with cars. Many are killed on roads in spring and summer, especially after rains. Most don’t survive car hits, and only a few end up in the hands of veterinarians and other animal care experts and recover from their injuries. However, unless they are returned to their home range in the wild, where they can breed and produce more turtles, they are as good as dead to the wild population.
Farms and neighborhoods with nearby woods offer some good habitat for box turtles. There are places for laying eggs, open areas for sunbathing, shady spots for cooling down, and possibly food and water. But life can be dangerous there too. In addition to car traffic, home lawn mowers and farm machinery injure and kill many box turtles every year. Or they may be accidentally burned in leaf piles that have been left for a while and where they have taken shelter. Dogs that run free are another problem. They injure and kill many box turtles every year. Children and adults often take box turtles they find in the woods or on the road and keep them as pets, intending to give the turtle a nice, safe home. But few people stop to think . . . that when box turtles are collected as pets, fewer animals are left to breed in the wild so fewer young are born there. This hurts the wild population. People may also hurt box turtles populations if they put plants around their homes that invade and degrade box turtle habitat. A good example is English ivy, a common landscaping plant. It invades the forests, forming thick carpets that prevent native vegetation, including plants that box turtles eat, from growing. Ivy also grows up trees, weighing down branches and causing them to break.
So what can you do to help box turtles? There are several things you can do locally. First, evaluate your own yard or property with respect to its habitat quality and threats. Mowing your grass in the middle of a hot summer day is the safest time to avoid turtles because this is the time when box turtles are most likely to be hiding in the bushes and cool forests, away from open, grassy areas. If your family burns leaves, be sure that they do it right after raking them up so that small animals, including box turtles, don’t have time to move in and hide in the leaf piles. Work with other neighbors to create wildlife-friendly zones that consist of native plants and wide forest buffers around streams and connect to other wildlife corridors. Another step you can take to help wild box turtles is to make sure that dogs in your neighborhood are walked on a leash. They shouldn’t run freely. Don’t support scavengers, like raccoons, that eat box turtles. Don’t feed them or leave pet food out at night. Make sure that predators can’t reach your bird feeders, and that your garbage cans are tightly shut. If you have a pond in your yard, make it turtle-friendly. The entire edge of the pond should have a gentle slope, so a turtle that stops by for a swim can easily get out anywhere along the edge. A turtle will swim to where it wants to get out of the water, and if it can’t, it may just keep swimming in place until it drowns. Sad but true!
If you own large acreages of forest land, particularly hardwood and bottomland forest, attempt to minimize its fragmentation by roads and utility rights of way, and promote structural and species diversity within the forest. Leave large blocks of interior forest intact by concentrating harvest regimes or small clearcuts on the outer edges. Keep your forest free from invasive non-native plant species.
If you see a box turtle on the road and you can safely pick it up, help the turtle across. Put it off to the side of the road in the direction it was headed. Don’t turn it around! Also, don’t take the animal home, and don’t move it to a place far away that you think will make a better home. Many box turtles will not settle down in a new area, and will just try to get back home. They may cross roads and face other dangers during their travels.
If you want to own a box turtle, first contact your state wildlife agency to see if it’s legal. If it is, then contact your local reptile club. They may have turtles that are available for adoption. Also, they can give you expert advice on how to take good care of your new pet. Don’t collect a wild box turtle, and don’t buy one. Most box turtles sold in stores were collected in the wild. Keep in mind that owning a box turtle is a major commitment. Your turtle will likely live longer than you do. It will never enjoy being held or played with. You cannot house it in a small aquarium. It needs a big pen—outdoors is best—and a special, rather expensive diet. If you do own a box turtle, and don’t want it any longer, don’t release it. It may not survive and may pass on diseases to wild turtles. Contact your local reptile club and ask them to help you find a new home for your pet.
You and your children could also get involved in turtle, or wildlife, or habitat conservation efforts locally. Contact your state herpetologist, the Virginia Herpetological Society, local nature center or park, to see if there are projects that are suitable for volunteers. Virginia Commonwealth University’s Rice Center, research is being conducted on turtle migration by outfitting them with radio transmitters then following their radio signal. This provides valuable information about their home range and habitat preferences. Partners for Amphibian and Reptile Conservation (PARC) is another good organization to join and offers newsletters, management publications, and events on their website
Write your state highway administration and ask them to support programs to reduce the amount of land that is mowed along public roadways. Under this program, fewer animals are likely to be injured and killed. Support programs to install passageways that allow wildlife to safely go over or under roadways. Of course, an expensive passageway isn’t always possible. If you know of an area near you where lots of box turtles are hit by cars, try to rally local support for putting in a fence to steer turtles to the safest possible crossing.
Of course, the most important step we can all take to save box turtles is to protect large wilderness areas, free of roads and vehicle traffic, where these turtles live. Support one of the many conservation organizations that buy and protect these places. The future of the eastern box turtle depends on us. Get involved, and help to give them a future.
For more information on box turtles, please visit the MATTS website at www.matts-turtles.org.
Photo: Male (left), female (right) by Sandy Spencer.